1. Technical Field
The present invention relates to methods of fabricating aesthetic and reconstructive surgical implants. More specifically, the present invention relates to methods of generating custom implants.
2. Background Art
After serious injury or disease, restoration of normal function, symmetry, and appearance can require surgery involving implanting materials to reshape the affected area of the body. Implants are also used to augment the shape and volume of normal anatomic regions of the body for aesthetic purposes. For the most part, commonly used implants are generic, pre-fabricated shapes and sizes that must be fit to each individual as best as they can. In other words, the majority of implants available are not specifically tailored to a patient and do not take normal asymmetry or other unique qualities into account.
There are several methods of generating implants that are currently used. U.S. Pat. No. 7,747,305 to Dean, et al. is one particular method of generating an implant based on a 3D CT scan. The '305 patent discloses a computer aided design method for producing an implant for a patient prior to operation comprising the steps of: generating data with a non-invasive 3D (3-dimensional) scan of the patient's defect site that digitally represents the area that will receive the implant; designing and validating an implant on a computer based on digital data generated from a volume image of the patient; and fabricating the implant based solely on the implant design data generated on computer.
U.S. Patent Application Publication No. 2006/0212158 to Miller generally discloses a device and method of manufacturing and implanting a custom subtalar arthroereisis implant having side surfaces, which are mirrored in topography with the sinus tarsi of a patient. The implant is formed using images of the patient standing in a weight bearing position with their sinus tarsi and the surrounding bone structure in an anatomically correct alignment. These 3D images can be obtained by a CAT scanner or an MRI device. Formation of the implant can be accomplished by three dimensional printers or computer driven mills. Once implanted, the implant urges and maintains the anatomically correct alignment thereby minimizing any patient tendency for abnormal motion between said patent's talus and calcaneus.
U.S. Patent Application Publication No. 2006/0212158 to Feldman generally discloses a device and method of manufacturing and implanting a custom subtalar arthroereisis implant having side surfaces, which are mirrored in topography with the sinus tarsi of a patient. The implant is formed using images of the patient standing in a weight bearing position with their sinus tarsi and the surrounding bone structure in an anatomically correct alignment. These 3D images can be obtained by a CAT scanner or MRI device. Once the image is sent to the computer, 3D modeling software (with physics modeling) can be used (Mimics Software Suite Materialise) to modify the implant. The implant can be formed by a three-dimensional printer or CNC machine. Once implanted, the implant urges and maintains the anatomically correct alignment thereby minimizing any patient tendency for abnormal motion between said patent's talus and calcaneus.
Custom implants can be developed from MRI or CT scans as in the methods above; however, they have several drawbacks. Patients receive radiation from CT scans and both MRI and CT scans are quite expensive to perform. The implants must generally be fabricated off-site at a laboratory or manufacturing location with injection molding and require a turn-around time of several days to several weeks. They can be unshaped materials (blocks) that are carved by hand, which is tedious and inaccurate. They do not allow for visualization of a simulated surgical outcome. Also, they do not allow for customization with virtual 3D external photographs. They do not visually predict the soft tissue modifications that will occur after implantation.
Therefore, there remains a need for a method of complete customization of an implant for a patient with on-site implant creation within hours that is lower cost than present methods.